Palette transporting mechanism and assembly line using the mechanism

ABSTRACT

It is the pallet conveying mechanism to move a pallet P arrived at an end point  17   b  of a friction conveyer FC 2  to a starting point  7   a  of a friction conveyer FC 1  in just as it is the direction without turning. The pallet conveying mechanism is comprised of rollers  34  having a flange portion  34   a  to contact with the pallet P by arranging along a main frame  31  provided so as to connect the friction conveyer FC 1  and FC 2  with each other and a drive mechanism  35  for driving rollers  34.

FIELD OF THE INVENTION

[0001] The present invention relates to a conveying mechanism of a pallet having a vehicle body and an assembling line using it.

BACKGRAND ART

[0002] A vehicle assembling line is to assemble a vehicle by attaching several kinds of parts to a vehicle body while the vehicle body is transferred by a hunger or by a pallet carried along a conveying line. Hereupon, a wiring for an electric system, an interior parts such as an instrumental panel and a seat, parts for underbody such as engine or tire, and exterior parts such as mirror or wiper are parts to be attached to the vehicle body.

[0003] Of these, a wiring for electric system and a part of interior parts such as the instrument panel are manually attached by workers with hand to the vehicle body loaded onto the pallet circulating through a liner-arrangement or a flat loop-arrangement conveying line. Especially, the assembling line installed the conveying line as a flat loop-arrangement can be widely used because the constitution of the conveying line can be simplified, in addition, utilization efficiency of a factory site can be improved.

[0004] Hereupon, as a conventional example of the assembling line installed the conveying line as a flat loop-arrangement and the pallet conveying mechanism used for this assembling line, some of these are disclosed in Japanese Unexamined Patent Publication Sho.58-22633 or Japanese Examined Patent Publication Sho.61-33743.

[0005] The assembling line according to Japanese Unexamined Patent publication Sho.58-22633 is comprised of a pair of conveying lines and a pair of traverse lines connected to each other. Rails established along each line and a moving mechanism to move the pallet along the rails are applied for the pallet conveying mechanism.

[0006] Furthermore, the assembling line according to Japanese Examined Patent publication Sho.61-33743 has a pair of conveying lines and a traverse line connected to each other. Additionally, the pallet conveying mechanism used in this assembling line is comprised of a rack gear provided along the traverse line and a traversor equipped with the pallet to move from one edge to the other edge of a traverse line. Moreover, the traversor has the constitution including a drive mechanism and a tuning table engaging with a rack gear to turn the pallet by the rack gear.

[0007] According to this pallet conveying mechanism, the pallet is loaded onto the traversor to be transferred from one end portion to the other end portion of the traverse line, at the same time, it is turned 180° around by a turning of the tuning table.

[0008] However, this assembling line has a problem such that the pallet conveying mechanism is complicated in structure. More specifically, the pallet conveying mechanism according to Japanese Unexamined Patent Publication Sho.58-22633 has a mechanism to slide the pallet along rails. Therefore, the pallet is required to have the mechanism capable of moving for not only lengthwise direction but also breadthwise direction and means for switching the mobile direction. Consequently, these cause the pallet conveying mechanism to be complicated in structure.

[0009] On the other hand, the pallet conveying mechanism according to Japanese Examined Patent Publication No.61-33743 has a mechanism to turn the pallet with conveying. Therefore, this causes the mechanism to be complicated for conveying the pallet. Meanwhile, since the following pallet can not be conveyed until the traversor is returned to the original position after conveying the pallet. Consequently, this has a problem such that it takes much time to convey the pallet on the traverse line.

DISCLOSURE OF THE INVENTION

[0010] Accordingly, the object of the present invention is to provide the pallet conveying mechanism capable of rapidly circulating the pallet through a simple mechanism, and the assembling line using this pallet conveying mechanism.

[0011] The invention regarding claim 1 of the present invention is the pallet conveying mechanism, which connects a first conveying line and a second conveying line opposing to said first conveying line and carries the pallet from the end point of the first conveying line to the starting point of the second conveying line comprising a plurality of rollers arranged so as to move the pallet perpendicularly to the conveying directions of the first conveying line and the second conveying line, a driving means for rotating rollers, and a guide means for preventing the pallet from veering while the pallet is being conveyed. The pallet conveying mechanism constituted in this way can convey the pallet from the second conveying line to the first conveying line without turning. Additionally, providing the guide means can prevent the pallet from veering when said pallet is being conveyed from the first conveying line to the second conveying line, consequently, the pallet can be conveyed more rapidly.

[0012] Moreover, the invention regarding claim 2 is an assembling line comprising a first conveying line, a second conveying line, a pallet conveying mechanism as set forth in claim 1 connecting the end point of the first conveying line and the starting point of the second conveying line, and a traverse line connecting the end point of the second conveying line and the starting point of the first conveying line, wherein, parts are attached to a vehicle body loaded onto the pallet while the pallet is circulated through the assembling line.

[0013] The assembling line constituted in this way can transfer the pallet rapidly without turning from the end point of the first conveying line to the starting point of the second conveying line due to a sliding mechanism. Consequently, this simple mechanism can efficiently circulate the pallet to assemble the vehicle body.

[0014] Furthermore, the invention regarding claim 3 is the assembling line as set forth in claim 2 wherein the traverse line has a turning table at both ends of the traverse line to turn the pallet 90° around.

[0015] According to the assembling line constituted in this way, turning the pallet 180° around on the traverse line can always prevent the vehicle body loaded onto the pallet from veering in the direction of the first and second conveying line. Consequently, the working efficiency of workers can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a whole structural view of a vehicle assembling line including an assembling line of the present embodiment.

[0017]FIG. 2 is a schematical view of an assembling line of the present embodiment seen from top.

[0018]FIG. 3 (a) is a cross sectional view of a friction conveyer, (b) is a view of pallet seen from top.

[0019]FIG. 4 (a) is a view of a first turning table seen from top, (b) is a side view of a first turning table.

[0020]FIG. 5 (a) is a partial enlarged view of a second traverse line, (b) is a side cross sectional view of (a).

[0021] FIGS. 6 (a), (b) are an explanatory view to explain a movement of a drop lifter used in an assembling line.

[0022] FIGS. 7 (a), (b) are an explanatory view to explain a movement of a drop lifter used in an assembling line.

BEST MODE FOR CARRYING OUT THE INVENTION

[0023] The embodiment of the present invention is described in detail with reference to drawings.

[0024]FIG. 1 is a whole structural view of the vehicle assembling line including the assembling line of the embodiment, FIG. 2 is a schematical view of the assembling line of the present embodiment seen from top, FIG. 3 (a) is a cross sectional view of a friction conveyer comprising the assembling line.

[0025] Besides, in the present embodiment, a lengthwise direction is a direction of the vehicle body length and a conveying direction of each conveyer. On the other hand, a lateral direction is the breathwise direction of the vehicle body and a perpendicular direction to a conveying direction of each conveyer.

[0026] First of all, a whole structure of the vehicle assembling line L is described with reference to FIG. 1. The vehicle assembling line L is to assemble the vehicle through conveying the vehicle body F along arrow marks of a drawing. And it is classified as a main line, a sub-line and a door assembling line depending on a region. The main line is comprised of a plurality of assembling zone classified several kinds of parts attaching to a vehicle body F depending on attaching region (for example, interior, exterior and underbody, etc.) such as a wiring zone WZ for electric system, an interior zone IZ, a underbody zone UZ, an exterior zone EZ and a combination zone CZ. The sub-line is comprised of an engine sub-assembling. The door assembling line is comprised of FR door line and RR door line connected to the main line in case of necessary.

[0027] Hereupon, each zone will be described.

[0028] First of all, the wiring zone WZ is a zone wherein an electric wiring of the vehicle and LAN wiring, pipeline, etc. for inside of the vehicle are integrally attached. The vehicle body F is conveyed by an overhead conveyer OC1 on the upper portion thereon while the vehicle body F is conveyed by a friction conveyer FC1 on the lower portion thereon.

[0029] The interior zone IZ is a zone wherein interior parts and floor parts, etc. are integrally attached to the vehicle body by transferring them with friction conveyors FC2 and FC3. Hereupon, an instrumental panel, a pedal and each linings, etc. are attached to the vehicle body F. Besides, an overhead conveyer OC2 is provided in between the friction conveyer FC1 and the friction conveyer FC2 to transfer the vehicle body F from a second floor to a first floor.

[0030] The underbody zone UZ is a zone wherein parts for an underbody of the vehicle are integrally attached. Parts for underbody, suspension, engine and tires, etc. are attached to the vehicle body F being conveyed by an over head conveyer OC3.

[0031] The exterior zone EZ is a zone wherein exterior parts are integrally attached to the vehicle body. A window glass, a seat and a bumper, etc. are attached to the vehicle body F being conveyed by a friction conveyer FC4.

[0032] The combination zone FZ is a zone wherein a functional confirmation is carried out for any kinds of parts and equipment attached on the each assembling zone on the upper portion. Hereupon, this functional confirmation is to confirm turning on the light and connecting terminal, etc.

[0033] Secondly, the assembling line 1 of the present embodiment is described.

[0034] The assembling line 1 shown in FIG. 2 is formed as one portion of the vehicle assembling line L shown in FIG. 1. It is the flat loop-arrangement assembling line comprising the friction conveyer FC1 on the lower portion of the wiring zone WZ for an electric system, the friction conveyer FC2 on the upper portion of the interior zone IZ, and the first traverse line 2 and the second traverse line 3 connecting with said friction conveyer FC1 and FC2.

[0035] Besides, in the present embodiment, the friction conveyer FC1 is indicating the second conveying line described within the confines of claim, similarly, the friction conveyer FC2 is indicating the first conveying line, and the first traverse line 3 is indicating the traverse line respectively.

[0036] The friction conveyer FC1, as indicating in FIG. 2 and FIG. 3 (a), has two rails 6, 6 established in parallel by fixing means 5 a on the bottom face of a slender pit 5 formed on a floor face 4 to transfer the pallet P along these rails 6. Hereupon, the pallet P is transferred by a driving portion 8 and a stopping portion 10 provided on a starting point 7 a (right end in FIG. 2) and an end point 7 b (left end in FIG. 2) of the friction conveyer FC1. Besides in FIG. 2, the pallets P are positioned at intervals on the friction conveyer FC1. But actually, each pallet P is positioned such that a front face 9 a is contacted with a rear face 9 b of the other pallet P to serve the rear pallet P to push the front pallet P for moving on the rail 6.

[0037] Hereupon, the driving portion 8 is comprised of a rotatable cylindrical-shaped drive roller 8 a and a roller drive motor 8 b to rotate a drive roller 8 a. The drive roller 8 a is provided such that the peripheral surface is contacted with a side surface 9 c of the pallet P to push out the pallet P by transmitting a torque generated in the driving roller 8 a to the side face 9 c of the pallet P through driving the roller drive motor 8 b.

[0038] On the other hand, the stopping portion 10 causes a friction on the surface between the pallet P and the stopping portion 10 through rotating a lower rotating speed than that of the drive roller 8 a to stop the pallet P. The constitution is the same as the driving portion 8.

[0039] Besides, in FIGS. 2, 12 is guide roller provided to stabilize the movement of the pallet P when driving or stopping. However, the guide roller 12 is not connected with a drive motor but it is contacted with a side face 9 c of the pallet P, at the same time, it only rotates in accordance with the movement of the pallet P.

[0040] What is more, the driving portion 8 and the stopping portion 10 can be also constituted as movable on a stand-by position away from the palate P with a predetermined distance when not using In case of this, when the pallet P is pushed out, the drive roller 8 a moves so as to contact with the side face 9 c of the pallet P from a stand-by position. Moreover, the drive roller 8 a is returned to the original stand-by position again after the pallet P was pushed out. On the other hand, the stopping portion 10 keeps the condition of remaining stay on the stand-by position for this moment. Additionally, when stopping the pallet P, the drive portion 8 is waiting on the stand-by position, in the meantime, only the stopping portion 10 moves so as to contact with a side face 9 c of the pallet P to stop the pallet P.

[0041] Hereupon, as indicating in FIGS. 3 (a) and (b), the pallet P using for conveying the vehicle body F has a slender shape wherein four holding portions 13 are provided on the symmetrical position for the lengthwise direction of the pallet P to support the vehicle body F. What is more, concave portions 14 are formed on the inner position than the holding portion 13 on the pallet to avoid the protruded portion of the vehicle body F. This allows the height from the pallet P to the vehicle body F to be shortened. Consequently, a work for attaching a wiring part PW to the vehicle body F can be easy.

[0042] Additionally, a plurality of positioning grooves (not shown) is formed in accordance with a type of vehicles (the length of vehicle body F) on the upper surface of the holding portion 13 to always maintain an invariable position for loading the vehicle body F. This is the constitution capable of responding to different type of vehicles.

[0043] Moreover, wheels 16 axially supported by a plurality of bearing 15 are allocated to under the pallet P. When these wheels 16 are skidded on the rail 6, 6 of the friction conveyer FC1, the pallet P can be moved along the rail 6, 6. Besides, a flange 16 a is provided on the wheel 16 to avoid derailing from the rail 6.

[0044] Furthermore, the friction conveyer FC2 is the conveying line to attach the interior parts PI such as an instrumental panel to inside of the vehicle body F. The structure is the same as a one of the friction conveyer FC1 for omitting the explanation.

[0045] Next, the first traverse line 2 and the second traverse line 3 are explained.

[0046] The first traverse line 2 is to move the vehicle body F loaded onto the pallet from the end point 7 b of the friction conveyer FC1 to the starting point 17 a of the friction conveyer FC2. As indicating in FIG. 2, it has a first turning table 21 and a second turning table 22 to turn the pallet P 90° around and a conveying line 23 between tables to move the pallet P from the first turning table 21 to the second turning table 22.

[0047] The first turning table 21, as indicating in FIGS. 4(a), (b), has two rails 6, a frame body 24 to support the rail 6, a rotary center portion 25 positioned on the center of this flame body 24 for equipping with a rotary shaft, and a rotary driving means 26 provided under the frame body 24 to rotate the frame body 24 around a center of a rotary center portion 25.

[0048] The frame body 24 has the side frames 24 a provided on a parallel to the rail 6 and the connecting frames 24 b to connect the side frames 24 a with each other. The stopping portion 10 to stop the pallet P introducing into the first turning table 21, the driving portion 8 to push out the pallet P into the conveying line 23 between tables and the guide roller 12 are fixed on the frame body 24. Besides, 24 c is an auxiliary frame body having a role of the auxiliary when fixing the driving portion 8 and the stopping portion 10 on the frame body 24. The frame body 24 and the rotary center portion 25 are connected with each other through this frame body 24 c.

[0049] Moreover, the rotary driving means 26 is comprised of four wheels 27 provided under the surface of the frame body 24 and the wheel driving motor 28 to rotate the wheel 27. The rotary driving means 26 rotationally moves the wheel 27 along the annular guide ring 29 by driving the wheel driving motor 28 through a signal from a controlling portion (not shown) to turn the first turning table 21 by 900 around toward a predetermined direction.

[0050] Also, the second turning table 22 is to feed the pallet P received from the conveying line 23 between tables to the friction conveyer FC2 after turning the pallet P by 90° around. It is the same structure as the one of the first turning table 21 for omitting an explanation.

[0051] Moreover, the conveying line 23 between tables has two rails 6 and it has a role of delivering the pallet P pushed out from the driving portion 8 of the first turning table 21 to the second turning table 22 in just as it is the direction.

[0052] What is more, the second traverse line 3 is described with reference to FIG. 2 and FIGS. 5 (a), (b).

[0053] The second traverse line 3, as indicating in FIG. 2, is to move the pallet P arrived at the end point 17 b of the friction conveyer FC2 to the starting point 7 a of the friction conveyer FC1 in just as it is the direction without turning. As indicating in FIGS. 5(a), (b), that structure has the main frame 31 having a concave-shaped section to avoid wheels 16 of the pallet P, the side frame 32 provided on the side of the main frame 31 at a regular intervals, a plurality of rollers 34 formed by the main frame 31 and the side frame 32 and arranged on two abreast of grooves 33 perpendicular to the conveying direction of the pallet P on the friction conveyers FC1, FC2, and the driving mechanism 35 to drive the rollers 34. Besides, a cover 36 to protect the driving mechanism 35 is provided above the side frame 32.

[0054] Additionally, as indicating in FIG. 2, the rail 6 a to receive an empty pallet P from the friction conveyer FC2, or to feed an empty pallet P to the friction conveyer FC1 is established on both ends of the second traverse line 3. This rail 6 a is capable of moving up and down. When the pallet P is moved by the rollers 34, these rails 6 a are moved downward, therefore, the pallet P can be moved in traverse direction along the rollers 34. Besides, driving and stopping the pallet P is carried out by the driving portion 8 and the stopping portion 10 provided on the end frame 31 a allocated to both ends of the main frame 31.

[0055] Hereupon, the roller 34 has the rotary shaft 37. The rotary shaft 37 is axially supported on the main frame 31 and the side frame 32 by a bearing (not shown), a flange 34 a of a guide means is provided on the peripheral portion of a sub frame side 32 of the rollers 34. This flange 34 a is provided so as to be contacted with a front face 9 a or a rear face 9 b of the pallet P to prevent the pallet P from veering or jumping out of the second traverse line.

[0056] The drive mechanism 35 is comprised of a drive mechanism motor 38 provided as one per a plurality of rollers 34 allocated in one row, a rotary transmission box 39 made of such as a gear (not shown) to transmit the rotation of the drive mechanism motor 38 to the rotary shaft 37, a sprocket 40 provided in the rotary shaft 37 and a chain 41 winded around the sprocket 40. When the drive motor 38 is driven, the chain 41 is also driven in response to this, consequently, this causes the roller 34 arranged in one row to be rotated.

[0057] Besides, the roller 34 equipped with a flange 34 a and the drive mechanism 35 comprise the pallet conveying mechanism described within the confines of claims.

[0058] Next, the assembling work of the vehicle body F in the assembling line 1 is described.

[0059] First of all, the vehicle body F conveyed by the over head conveyer OC1 indicating in FIG. 1 is transferred and loaded onto the pallet P by the drop lifter DL. As shown in FIG. 2, the drop lifter DL is installed on the starting point 7 a of the friction conveyer FC1 and the end point 17 b of the friction conveyer FC2 to have the constitution as shown in FIG. 6 and FIG. 7. That is to say, when the vehicle body F arrives at the drop lifter DL (FIG. 6 (a)), sliders 52 are risen along two posts 51 such that a holding portion 53 fixed on the slider 52 supports a side sill of the vehicle body F. Then, the arm opening and closing portions provided on the upper portion of the posts 51 open the arm portions 54 of the over head hanger 50 toward traverse direction (FIG. 6 (b)), the vehicle body F supported by only the holding portion 53 is transferred downward as shown in FIG. 7 (a) to be transferred and loaded onto the pallet P waiting in lower portion (FIG. 7 (b)).

[0060] Thereafter the controlling portion (not shown) drives a drive roller 8 a of a drive portion 8 to push out the pallet P from the starting point 7 a to the end point 7 b of the friction conveyer FC1 after confirming through such as light sensor whether the vehicle body F is loaded onto the pallet P.

[0061] The worker gets into the pallet P or the vehicle body F to attach parts PW to inside of the vehicle before the pallet P arrives at the end point 7 b of the friction conveyer FC1. And the vehicle body F which was ended to the functional guarantee check of the attached parts PW arrives at the end point 7 b of the friction conveyer FC1 with loading onto the pallet P to be decelerated and stopped by the stooping portion 10 of the end point 7 b.

[0062] Hereupon, the controlling portion drives the drive roller 8 a of the drive portion 8 to push out the pallet P to the first turning table 21 after confirming the direction of the first tuning table 21 of the first traverse line 2.

[0063] The pallet P introduced to the first tuning table 21 is stopped on the rail 6 of the first tuning table 21 by the stopping portion 10 fixed on the frame body 24. Then a wheel drive motor 28 rotates a wheel 27 to turn the pallet P by 90° around counter clockwise toward the conveying line 23 between turning tables.

[0064] After turning the pallet P is completed, the driving roller 8 a of the driving portion 8 pushes out the pallet P to the conveying line 23 between turning tables and the pallet P arrives at the second turning table 22 via the conveying line 23 between turning tables. Hereinafter, the pallet P is pushed out to the friction conveyer FC2 after turning the pallet P by 90° around clockwise in the same way of the operation on the first turning table 21.

[0065] The pallet P is conveyed on the friction conveyer FC2 in the same way of the operation on the friction conveyer FC1, in the meantime, the worker attaches interior parts PI such as instrumental panel to the vehicle body F.

[0066] Then, the pallet P is stopped by the stopping portion 10 on the end point 17 b of the friction conveyer FC2 where the vehicle body F is transferred and loaded onto the over head hanger 50 of the over head conveyer OC2 by the drop lifter DL.

[0067] And after the vehicle body F is transferred and loaded onto the overhead hanger 50, an empty pallet P is introduced to the second traverse line 3 through driving a drive roller 8 a.

[0068] After the empty pallet P is introduced to the second traverse line 3 and the flange portion 34 a of the roller 34 is contacted with the front face 9 a of the pallet P, a driving means 35 drives a chain 41 to rotate a plurality of rollers 34 arranged in two rows.

[0069] Rotating the roller 34 allows the pallet P to be transferred on the second traverse line 3 in traversal direction toward the friction conveyer FC1 from the friction conveyer FC2.

[0070] When the pallet P arrived at the end portion of the friction conveyer FC1 side of the second traverse line 3, the driving means 35 is stopped and the pallet P is pushed out to the starting point 7 a of the friction conveyer FC1 by the drive portion 8.

[0071] Repeating aforementioned movement allows the pallet P to be transferred by circulating through the flat-loop arrangement assembling line 1. This assembling line 1 has a symmetrical configuration for a lengthwise conveying direction of the pallet P. Therefore, a following vehicle body F can be loaded on the pallet P without turning on the second traverse line 3. This allows the second traverse line 3 to have a simple structure without a turning mechanism. Additionally, a time period to convey the pallet P can be shortened because of not involving in a turning movement.

[0072] What is more, since the pallet is turned by 180° around on the first traverse line 2, the front portion of the vehicle body F is always ahead of the conveying direction of the friction conveyer FC1 and FC2, consequently, the worker can easily work and the working efficiency of assembling the vehicle body F can be improved. However, though forward and backward of the pallet P is turned whenever the pallet P is rounding around the assembling line 1, this has no influence on loading the vehicle body F onto the pallet P and attaching work of the parts PW, PI to the vehicle body F because the pallet P has a symmetrical configuration for the lengthwise direction.

[0073] Besides, the present invention is not restricted to the embodiment, but it is widely applied. For example, the first and second conveying line can be the conveying line equipped with a well-known conveying means such as a chain conveyer or a belt conveyer for conveying the pallet P instead of the friction conveyer FC1, FC2.

[0074] Furthermore, it can also be the assembling line 1 provided a lift to hoist and bring down the pallet P for delivering between the friction conveyer FC1, FC2 and the first traverses line 2, the second traverse line 3 respectively by providing the first traverse line 2 and the second traverse line 3 on the position higher or lower than a floor face 4 wherein the friction conveyer FC1, FC2 are installed.

[0075] What is more, the pallet P can be turned 180° around on the first turning table 21 without installing the second tuning table 22 on the first traverse line 2. The assembling line 1 can be simple mechanism due to a reduction of a turning mechanism.

[0076] Additionally, the constitution of the first traverse line 2 is the same as that of the second line 3 and it can also be the mechanism that the vehicle body F loaded on the pallet P received from the friction conveyer FC1 is delivered to the friction conveyer FC2 without turning.

[0077] Then, the guide means can also be a roller provided so as to be contacted with a side face 9 c of the pallet P instead of the flange 34 a formed along the periphery of the roller 34.

INDUSTRIAL APPLICABILITY

[0078] The present invention is the pallet conveying mechanism equipped with rollers having a flange to contact with the pallet. This conveying mechanism is to convey the pallet from the second conveying line to the first conveying line without turning. Therefore, the flange can prevent the pallet from veering while the rollers allow the pallet to be moved in parallel. Consequently, the pallet can be rapidly conveyed through a simple conveying mechanism.

[0079] Additionally, since the assembling line is a loop arrangement using said pallet conveying mechanism, the simple conveying mechanism can circulate the pallet efficiently to assemble the vehicle body.

[0080] Moreover, since the tuning table to turn the pallet is provided on both ends of the traverse line to convey the pallet from the first conveying line to the second conveying line, the direction of the vehicle body loaded onto the pallet can be always invariable for the conveying direction of the first and second conveying lines. Consequently, the working efficiency of workers can be improved. 

1. A pallet conveying mechanism, which carries a pallet from the end point of said first conveying line to the opposing starting point of said second conveying line, comprising; a plurality of rollers arranged so as to move said pallet perpendicularly to the conveying directions of said first conveying line and said second conveying line, a driving means for rotating said rollers, and a guide means for preventing said pallet from veering while said pallet is being conveyed.
 2. An assembling line comprising; a first conveying line, a second conveying line, a pallet conveying mechanism as set forth in claim 1 connecting the end point of said first conveying line and the starting point of said second conveying line, and a traverse line connecting the end point of said second conveying line and the starting point of said first conveying line, wherein, parts are attached to a vehicle body loaded onto said pallet while said pallet is circulated through the assembling line.
 3. An assembling line as set forth in claim 2, wherein said traverse line has a turning table at both ends of the traverse line to turn said pallet 90° around. 